I understand that to provide accessibility to Host2 from Host1:
1) I can set up a VPN, but this is too much just for one communicating channel.
2) I can use SSH connection with remote forwarding (-R option), but again - this is too much
3) I can set up Jabber server on Host1 and Jabber client on Host2 and communicate through the XMPP messaging protocol - nice option but looking for more unattended solution

I'm interested in finding a software that allows to set up a persistent socket connection between these hosts and map web service port from Host2 to Host1.

Please advise to what type of proxy this scenario conforms and is there any software for that?

UPDATE: A good rephrase for this question: How to map a listening port from Host2 to Host1?

Thank you for the answer but I left one of the main points unclear - both hosts are in different networks... Would it change your answer or I'm missing something?
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forkerFeb 16 '10 at 14:59

You need some way of allowing host1 to send/receive data to host2, either by allowing traffic to be directly routed from one network to the other or by setting up a VPN connection. If host1 can't talk to host2 at all then you've got an air-gap between the networks and you're stuffed I'm afraid.
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PaoloFeb 16 '10 at 15:02

Sadly but that is the question - how to handle this air-gap, without VPN or SSH
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forkerFeb 16 '10 at 15:14